Abstract

The spectral properties and the coherence properties of Gaussian Schell-model beams propagating in dispersive and absorbing media are discussed. Unlike in free space, the ratio of the transverse spatial coherence length to the beam width is found to increase on propagation. Consequently, the beam becomes spatially more coherent as it propagates. Numerical results for the spectrum and for the degrees of spectral and of temporal coherence of the field are presented for some selected values of the beam parameters and for several values of the propagation distance. Propagation in a gain medium is also briefly discussed.

© 1992 Optical Society of America